In my current campaign, the party started out in Thornbare, a small town in a distant backwater of the empire. Its politics, economy, culture, and threats were all local in nature, and its population was very small, so I was able to take the time to create sketches for a couple dozen NPCs, draw a complete map of the town, and describe a brief history-- all just enough to flavor the party's interactions. Now that the party is gaining in levels and the scope of their challenges is growing, it's getting more important that details of the larger world start getting filled in. I knew that they would soon be traveling to the capital to seek assistance with a major quest, so the time had come to start thinking big and planning for a major urban environment.
As a DM who likes to be well-prepared, I found the notion of designing a city to be very daunting-- do I have to draw a map with every building marked? How many NPCs do I need to create, and how many locales? Visions of hundreds of pages of notes and maps swirled in my head, and I found myself feeling completely overwhelmed.
So I decided to start with broad strokes, thinking that if I could provide some high-level details of the city, this would inform the creation of lower-level features, from locales to NPCs.
I started by thinking about the general features of the city, sketching out a few paragraphs that would introduce it and provide a basis for answering more detailed questions later.
Think of famous cities in our world. London has its towers, San Francisco has the Golden Gate Bridge, Venice its canals, and Paris its various bridges and broad avenues. What is memorable or distinctive about the city that you are designing? Is its distinction architectural, demographic, or political in nature, or some combination of these?
In our world, the actual boundaries of a city are often obscured by miles and miles of suburbs. But suburbs are a relatively modern phenomenon; in a medieval setting, most cities were extremely compact (packing tens of thousands of residents into the area of one square mile) and the border between the city and its surroundings a little more sharply defined.
Since we're not bound to the strict rules of reality in designing a fantasy city, it's possible to make the appearance of the city as fantastical as we desire. Is the city surrounded by a magical boundary of some sort? Is it floating on the surface of a great lake, or even in mid-air? Does it cling to the cliffs of a massive mountainside, or is it completely underground? What does the party have to do to enter the city-- pass under an imposing gate, ride a ferry into a canal, or climb a vast stairway to the lower reaches of a cloud-swept cityscape? A dwarven city might be carved out from the insides of a mountain; an elven city may consist of interconnected platforms high in the trees above.
As a starting point, I pulled up Wikipedia and looked up a few large cities to see how the information on each was organized. I copied this organization into an OmiOutliner document to organize the general details that I would need to fill in to make the city come to life:
Some cities are deliberately created and designed according to a central plan, like Washington DC, while others are the result of a gradual and organic evolution over centuries, like London. Some cities thrive by virtue of their geographic location, such as a city that sits on a major trade route or that has access to an important river or sea. Others owe their existence to their strategic importance, as a defensive position between two kingdoms or the need for protection of a natural, cultural, or magical asset-- such as a life-giving spring, an important religious shrine, or a source of arcane power. Thinking about the reason for the city's existence can inform important design decisions and provide the seeds for NPCs that have an important role to play in the city's day-to-day life.
The government of a city might have a huge impact on its physical, architectural, and demographic makeup. Is the city strictly managed, with each district tightly controlled and governed? If so, the boundaries between districts might be enforced by walls, patrols of guards, or both. Is the government democratic, autocratic, technocratic, feudal, or under some other form of rule? A city ruled by mages will have a very different flavor from one that is run by competing noble houses, mercantile guilds, or a military council.
The location and its prevailing geographical features are important factors in the design of the city. There may be rivers that carve the city into distinct districts, or differently elevated strata of a mountaintop metropolis that each have their own defining characteristics. A city in an active volcano range may be surrounded by a moat of liquid lava. A coastal city will have a waterfront district filled with ships from different cities and countries around the world.
Does the population of the city represent the population of the country as a whole, with different ethnicities and races living side-by-side? Or is the city a manifestation of a caste-based system, where different social or ethnic strata are sharply divided geographically? The city might be the social and cultural center of the ruling class, for example, or a trade center where peoples of various backgrounds and social standing come together to exchange goods and services.
What makes the city tick? Is it the gears of government, the shouts and calls of merchants at the market, or the clink of coins in dark alleyways? A city needs an economy to sustain itself, and that economy may be local (as is the case of a city that serves as a financial center for local farmers and tradesmen), regional (a port that handles trade between multiple countries or regions), national (a capital city), or even extraterrestrial (a city that protects and manages access to otherworldly destinations and planes).
How do the people of the city move from place to place? Is there a systematic method of transportation, or is something special required? A city built on a river may have ferries to transport citizens between districts. A canal city may have water taxis, while an aerial city may provide magical transport between locales on floating platforms or on the backs of flying beasts of burden.
Defining the culture of the city can be a little tricky. You want to add enough flavor to set the city apart while allowing for enough variation to be interesting. A city of the arcane arts may have a large population of wizards, but daily life also requires people with more mundane professions and outlooks doing the hard work of keeping the city going. Think about what defines the city from a cultural perspective, and then what sort of people would likely be attracted to that culture. A city founded on the philosophical principles of open trade would probably support a thriving black market; a religious community may have its share of extremists, dissidents and heretics in addition to its prophets, pilgrims, and priests.
Keep in mind that culture does not form in a vacuum. The cultural mores of the city are likely strongly tied to its history and geography. A city that grew up as a defensive stronghold on the borders between two sharply defined geographical regions will have a more rigidly defined culture than a city that facilitates trade between nations or planes. Similarly, a city that formed around an important historical location, such as a sacred shrine or an arcane wellspring, will have been influenced greatly by the cultural defenders of that location; the priests or mages may form the ruling class, defining the social order and the types of activity that the city supports.
Once the broad strokes are defined, it's a lot easier to start filling in the details. The next article in this series will break the large challenge of city design into a series of smaller problems that are easily solved with just a little effort and creativity.